com.twitter.util.StringEncoder.scala Maven / Gradle / Ivy

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package com.twitter.util

import com.twitter.io.StreamIO
import java.io.{ByteArrayInputStream, ByteArrayOutputStream}
import java.nio.charset.{StandardCharsets => Charsets}
import java.util.Base64
import java.util.zip.{GZIPInputStream, GZIPOutputStream}

trait StringEncoder {
  def encode(bytes: Array[Byte]): String = new String(bytes)
  def decode(str: String): Array[Byte] = str.getBytes
}

/**
 * A utility for encoding strings and byte arrays to a MIME base64 string, and
 * decoding from strings encoded in MIME base64 to byte arrays.
 *
 * The encoding for strings is UTF-8.
 */
trait Base64StringEncoder extends StringEncoder {
  private[this] val encoder = Base64.getMimeEncoder(0, "\r\n".getBytes(Charsets.UTF_8))
  private[this] val decoder = Base64.getMimeDecoder
  override def encode(bytes: Array[Byte]): String =
    new String(encoder.encode(bytes), Charsets.UTF_8)
  override def decode(str: String): Array[Byte] = decoder.decode(str.getBytes(Charsets.UTF_8))
}

/**
 * A utility for encoding strings and byte arrays to a URL-safe base64 string,
 * and decoding from strings encoded in base64 to byte arrays.
 *
 * The encoding for strings is UTF-8.
 */
trait Base64UrlSafeStringEncoder extends StringEncoder {
  private[this] val encoder = Base64.getUrlEncoder.withoutPadding
  private[this] val decoder = Base64.getUrlDecoder

  override def encode(bytes: Array[Byte]): String =
    new String(encoder.encode(bytes), Charsets.UTF_8)
  override def decode(str: String): Array[Byte] = decoder.decode(str.getBytes(Charsets.UTF_8))
}

object StringEncoder extends StringEncoder
object Base64StringEncoder extends Base64StringEncoder
object Base64UrlSafeStringEncoder extends Base64UrlSafeStringEncoder

/**
 * A collection of utilities for encoding strings and byte arrays to and
 * decoding from strings compressed from with gzip.
 *
 * This trait is thread-safe because there are no streams shared outside of
 * method scope, and therefore no contention for shared byte arrays.
 *
 * The encoding for strings is UTF-8.
 *
 * gzipping inherently includes base64 encoding (the GZIP utilities from java
 * will complain otherwise!)
 */
trait GZIPStringEncoder extends StringEncoder {
  override def encode(bytes: Array[Byte]): String = {
    val baos = new ByteArrayOutputStream
    val gos = new GZIPOutputStream(baos)
    try {
      gos.write(bytes)
    } finally {
      gos.close()
    }
    Base64StringEncoder.encode(baos.toByteArray)
  }

  def encodeString(str: String): String = encode(str.getBytes("UTF-8"))

  override def decode(str: String): Array[Byte] = {
    val baos = new ByteArrayOutputStream
    val gis = new GZIPInputStream(new ByteArrayInputStream(Base64StringEncoder.decode(str)))
    try {
      StreamIO.copy(gis, baos)
    } finally {
      gis.close()
    }

    baos.toByteArray
  }

  def decodeString(str: String): String = new String(decode(str), "UTF-8")
}

object GZIPStringEncoder extends GZIPStringEncoder